Crankshaft



March 30, 1937.

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Patented Mar. 30, 1937 UNITED. STATES PATENT OFFICE I CRANKSHAFT Gustav A. Miller, Bloomington, Ill.

Application February I 2 Claims.

My invention relates to internal combustion engines, and has among its objects and advantages the provision of an improved crank shaft.

An object of my invention is to provide a crank shaft comprising two parts operatively connected together for rotation in opposite directions at a common R. P. M., whereby torsional vibration imparted to engines of the one-piece crank shaft type is eliminated.

Another object is to arrange the two parts of the shaft in axial alignment or substantially in end to end relation for association with cylinders arranged in a straight line, thereby eliminating the necessity for reconstructing the engine proper.

A further object is to provide a balanced engine eliminating the necessity for special mountings for the engine to secure smooth operation.

In the accompanying drawing:

Fig. 1 is a side elevation of an engine partly in section illustrating my invention;

Fig. 2 is a bottom plan view of the engine with the pan of the crank case removed;

Fig. 3 is a sectional view along the line 3-3 of Fig. 4 is a detail view of a different connection between the two crank shaft parts; and

Fig. 5 is a view illustrating another type of gear connection between the crank shaft parts.

In the embodiment selected to illustrate my invention, I make use of an internal combustion engine [0 comprising the usual cylinder and piston units l2 and connecting rods I4. My invention comprises a crank shaft made up of two parts l6 and I 8 each connected with four of the connecting rods l4 through the medium of conventional bearings 20.

While I have illustrated the invention as being embodied in an eight cylinder engine, it will be 4 understood that the construction is equally applicable to engines made up of a different number of cylinders. In the instant case the crank shaft part I6 is supported by a conventional end bearing 22, a center bearing 24, and an extra end bearing 26. Similarly, the crank shaft part I8 is supported by a conventional end bearing 28, a center bearing 36, and an extra end bearing 32 arranged in close relation with the bearing 26.

I operatively connect the parts l6 and I8 of the crank shaft through the medium of two herringbone gears 34 and 26, respectively. However, spur gears may be used, but it is believed that gears of the herringbone type provide a better 55 connection between the two parts in an engine 11, 1935, Serial No. 6,078

having the cylinders arranged in a straight line, as illustrated. I I

The two crank shaft parts l6 and I8 are arranged with their axes of rotation in parallel relation but sufficiently close to accommodate the straight line arrangement of the cylinders. In Fig. 3 I illustrate the axes of rotation of the crank shaft parts l6 and I8 as being arranged on opposite sides of the vertical axes of the cylinders, with the vertical axes passing between the pitch circles of the gears 34 and 36.

With the crank shaft parts l6 and I8 arranged according to the illustration of Fig. 2, the parts rotate in the directions indicated by the arrows 38 and 40 of Fig. 3, so that the connecting rods l4 throw inwardly. Rotation of the part l8 in the direction indicated permits its connection with conventional transmission mechanism. If, however, the parts l6 and I8 were changed so that the part l6 would lie in axial alignment with the position of the part l8, rotation of the parts should be reversed to make a proper connection with the conventional transmission.

In Fig. 4 I have shown a slightly different arrangement of gears for connecting the two crank shaft parts 44 and 46 in axial alignment. In this view the parts 44 and 46 are provided with bevel gears 48 and 50 operatively connected together through the medium of bevel gears 52 and 54.

The gears 52 and 54 are supported in bearings 55 and 58 supported by the bearings 60 corresponding to the end bearings 26 and 32. In this arrangement the units 44 and 46 rotate in opposite directions in the same way as the units 16 and I8. v

Another form of connection for the crank shaf t parts is illustrated in Fig. 5. In this form each crank shaft part 62 and 64 is provided with a gear 66 and 68, respectively, which gears are respectively arranged in mesh with gears 10 and 12. The gear 70 is made in one piece with the gear 74 arranged in mesh with a similar gear 76. The gear 16 is made in one piece with the gear 12. I have indicated diagrammatically at 18 shaft and bearing supports for the gears 10, 72, 14 and 16. Crank shaft parts arranged in axial alignment provide an ideal construction for engines of the V type, in that the arrangement permits the usual close relation between the angularly arranged groups of cylinders.

An engine equipped with my crank shaft may operate in the usual way with respect to the firing order of the cylinders, and the valves may be conventional and operated through the medium of the usual cam shaft 80. In Fig. 2, I have numbered the cylinder and pistonunits I2 individually from I to 8, reading from right to left. the same for use under various conditions of The firing order may be conventional as follows: service. 1, 6, 2, 5, 8, 3, '7, 4. This order is common to I claim: most of the present day straight-8 engine de- 1. In an internal combustion engine, a plural- 5 signs. In a six cylinder installation according ity of cylinders and pistons arranged in straight to my invention, and numbering the cylinders alignment, a. crank shaft comprising two parts from right to left, the firing order could be operatively connected together for rotation in 1, 5, 3, 6, 2, 4. In any case, the firing order is opposite directions, said crank shaft parts being arranged so that the explosions are alternately arranged in parallel spaced-apart relation, and 10 distributed between the two parts of the crank connections between the pistons and the crank shaft, or distributed so far as is possible. I proshaft. vide a two-piece crank shaft within a single 2. In an internal combustion engine, a pluralengine and arrange the firing order in such a ity. of cylinders and pistons arranged in straight manner that the forces making for tortional alignment, a crank shaft comprising two parts, 15 vibration are distributed between the two crank a gear connected with each part and meshing shaft parts. The distribution is such that each with the other gear for rotating the parts in force tends to negative the efiects of the pre-' opposite directions at a common R. P. M., the ceding force so that a balanced condition is longitudinal axes of the cylinders being aligned attained. in a plane corresponding to the meeting point 20 Without further elaboration, the foregoing will between the pitch circles of said gears, and conso fully explain my invention that others may, nections between said parts and said pistons. by applying current knowledge, readily adapt GUSTAV A. MILLER. 

